pill combination

Although phentermine is a proven weight loss medication and the most widely prescribed on the market, some doctors prefer to prescribe phentermine alongside other medications, with the intention that this combination maximizes the potential of the phentermine and increases the possibility of effective weight loss. Here we explain two of the most common phentermine pill combinations that doctors are currently prescribing, so you can understand more about how and why these combinations are specifically chosen.


Phen-Pro is the name given to the combination of phentermine and a low dose of one of the following: Prozac, Zoloft, Celexa, Luvox, trazodone, or Effexor. Although these second medications in the Phen-Pro combination are anti-depressants, their prescription alongside phentermine is not for the treatment of depression but rather is intended to help the phentermine work more effectively at promoting weight loss. Dr. Michael Anchors, who developed Phen-Pro and holds the patent for this combination, first tested the combination of phentermine and Prozac in 1995 and, based on his findings, believes that the addition of Prozac makes phentermine work more effectively and for a longer period of time.

Prozac, and other anti-depressants in the Phen-Pro combination, are types of Selective Serotonin Re-uptake Inhibitors (SSRIs), and are believed to increase the level of the neurotransmitter serotonin by inhibiting its reuptake. Serotonin is a naturally occurring appetite suppressant which curbs cravings and cuts off appetite, meaning that you will feel satisfied even when your stomach is not full. Therefore, it is thought that the combination of phentermine and the additional levels of serotonin promoted by the SSRI ingredient of Phen-Pro work together to inhibit appetite and help you lose weight by controlling hunger.

As with taking phentermine alone, there is the possibility of side effects with Phen-Pro. Additionally, as there is the possibility of further side effects caused by the interaction between the two medications, patients taking Phen-Pro should be vigilant and monitor their reactions very carefully. Some of the side effects which can occur as a result of Phen-Pro are jitteriness, nervousness, anxiety and restlessness, and the combination of phentermine and any SSRI also increases the risk of a rare but serious condition called serotonin syndrome. The symptoms of this, amongst others, are hallucinations, seizures, changes in heart rate, fever, blurred vision, nausea, vomiting and diarrhea, and you should contact your doctor immediately if you experience any of these symptoms.

pill combinations


Qsymia, which was previously called Qnexa, is the combination of phentermine and topiramate, an anticonvulsant drug that can cause weight loss as a side effect. The combination of topiramate and phentermine was previously prescribed off-label, meaning the combination was prescribed for weight loss without it being approved specifically for this use by the FDA, but in 2012 the FDA approved the weight loss medication Qsymia as the brand name for this combination.

Topiramate is prescribed for a variety of conditions, including as a means of counteracting the weight gain associated with numerous anti-depressants, and recent trials indicate that topiramate may have mood-stabilizing properties which can control certain unwanted behaviors and tendencies. It has also been investigated for use in treating various addictions and treating obesity by means of reducing binge eating, all of which may explain why it is effective in combination with phentermine.

The possible side effects of taking Qsymia are similar to those associated with taking phentermine. These include dry mouth, dizziness, constipation and insomnia, however through the inclusion of topiramate, further side effects may be experienced, such as drowsiness, changes in taste, and tingling sensations in the fingers and toes. These side effects are fairly common and often pass within days, but if you are taking Qsymia and experience more severe or prolonged side effects, or if you are concerned in any way about the symptoms you are experiencing, then you should consult your doctor immediately.

Other Phentermine Combinations

Phentermine can also be prescribed in other drug combinations, including with anti-diabetic drugs like Glucophage XR, with other anti-convulsants such as Zonegran, or with Norepinephrine-Dopamine Reuptake Inhibitor (NDRIs) such as Welbutrin SR. In certain cases these combinations may be prescribed to help treat other existing conditions such as sleep apnea, metabolic syndrome, and diabetes, while other combinations are intended to work together to increase the effectiveness of phentermine.

If you have been prescribed phentermine in combination with any other drug, it is important that your doctor explains to you why he or she has chosen this combination for you, what each medication does, how the two work together, and what possible interactions may arise as a result of the combination in order for you to know what to expect, both in terms of results and of possible side effects.

Finally, it must be stressed that these combinations are only safe if specifically prescribed by a doctor. Even if you have individual prescriptions for both medications, without being prescribed a certain combination by a doctor who is aware of all of your medical conditions and current medications, harmful drug interactions may occur as a result of self-medicating phentermine combinations.

Are you taking phentermine in combination with another medication? Let us know all about your experiences by commenting below!


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39 Responses

  1. I have been on Phentermine alone beginning in April 2013 and after 3 months I had lost about 20 lbs. went off of the phentermine for about 2 months and actually lost down to 285 then went back on it and am now down to 275 and have been able to keep the weight off. I wanted to see how my body would react with being off of it for the second time and stayed off for 3 weeks but was able to lose about 4 more lbs., so I am going back on it now for 3 more months to see how much more weight I can lose. My ultimate goal is to be down to 225 by Memorial day. And, by the way, I have not had any dramatic side effects on phentermine except for maybe dry mouth but that could also be caused by other prescription drugs that I take for cholesterol, but besides the dry mouth no side effects that I could discern.

    • I am curious of the outcome two years later 🙂

  2. For me Phentermine works maybe it will for you, too!!

  3. I take phentermine (half of a 37.5mg pill) with 30mg of cymbalta and 1mg of Ativan. I have had no strange reactions. occasionally my anxiety gets a little worse than usual and i take an extra ativan but other than that, the combo is working very well.

    • Hi Paige, Thanks for your feedback 🙂

      Great to hear it is working for you! If you are ever looking for weight loss support or a community forum to discuss weight loss topics and find some inspiration, then check out our weight loss forum by clicking here.

      I hope this helps, have a great day!

      Sally, Phentermine.com

  4. Phentermine makes me very cranky in the past so I got off it – I hate being so cranky. I’ve taken Prozac in the past during difficult times or times I’m very very stressed and it always works wonders with my moods. So I was wondering if I could take the combination of the two, the phentermine for the weight loss and the Prozac for the crankiness. Does anyone know if adding the Prozac helps with the crankiness caused by phentermine?

    • Hi Tonya, thanks for your message. Typically, the Prozac prescribed alongside phentermine is a way to make the phentermine more effective, as in Phen Pro, which is described in the article above. It may be possible to take Prozac alongside phentermine as a way to benefit from both these medications for their individual effects, but this would HAVE to be prescribed by a doctor – medications cannot be combined without the approval of a doctor. We’d advise you to talk to your doctor about this as a way to possibly overcome this side effect of phentermine while you lose weight.

      Hope that helps, have a great day!!

      Sally, phentermine.com

  5. I have been taking the phentermine/topamax combo with good results but I am starting to feeling like it is not working anymore. I am wondering if changing to the Phen Pro combo would work?

  6. Is anyone taking phentermine and phen caps together? And if so what r ur results. And do u take them together?

  7. Hi, I am on Fluoxitiene and wonder if it would be ok to take phentermine as well ?

    • Hey Mary, we advise you to ask your doctor as harmful interactions can occur when you take phentermine with other medications.
      Sally, phentermine.com

  8. Just started 37.5mg phen along with 10mg trazadone. Previously was on Phen 37.5 along. Has anyone taken the phen/trazadone combo? and if so, any positive weight loss?

  9. I am taking something called \”s-phen\” capsules 15-40M. I am trying to figure out what the s stands for and how many MGs I am taking of each medicine. It worked really well the first month. I lost 12 lbs. This month, my weight lose is slowing down. I also take Celexa as a separate medication. Can anyone help me? I guess I should of thought about it before I started taking it, but now I just want to know what it is that I am taking.

  10. Hi, when taking phentemine along with a anti depressant as a combination, would you take them both at the same time or would you take the phentermine in the mornining and the anti depressant at night before bedtime?

    • Hey Tonya,
      This would be something that your prescribing doctor should tell you – it could be different for different people, or it could depend on which particular anti-depressant. If you’ve been prescribed a phentermine combination and are unsure of when to take the anti-depressant then you should contact your doctor before proceeding with the medications.
      Sally, phentermine.com

  11. I have been on Qsymia for some time and am moving up to the 15mg dose. I also take 20 mg of fluoxetine (Prozac). I am nervous about the possible complications of the two medications, and am thinking that maybe I should half my fluoxetine med while I am on the higher dose of Q. I have not had any problems as of yet, but I don\’t want to risk anything. I only have 25 pounds left to lose and then would like to hopefully wean myself off of Q. How many people do you have knowledge of that have taken the 15mg dose and have also taken a 20 mg dose of Prozac and had no negative side effects? I have been doing some research and am not sure why my doctor and pharmacist didn\’t seem too nervous about this. –

  12. I am taking 15 mg of phentermine with pregabalin (Lyrica) 75 mg in the morning and 150 mg in the evening, also 0.5 clonazepam in the evening. Once a week I add 10 mg of Celexa for a day or two for serotonin boost, it helps tremendously. Also using 250 mg of HCG 3 times a week and a 50 mg of Masteron (Masteron is a steroid DHT derivative) every other day. I am on this cycle or therapy for a month, I started at 114 kg and 27% of body fat. After a month a have 109 kg and 20 % of body fat. I workout with weights 4 times a week and i do cardio 3-4 times a week for 30-50 minutes. I eat between 1500 and 2000 cal a day. I am an ex bodybuilder competitor and a personal trainer.

  13. When will a manufacturer make phentermine like it was in 2013 and before? Where you didn’t have to add another medication to make it work. I lost 30 pounds in 3 months back in 1990 and kept it off for 10 years. Then in 2007 I lost another 20 pounds. But now the meds work nothing like they used to. Hence the reads the doctors are prescribing meds to work with phentermine. When will the phentermine work like it used too?

  14. I want to know if it’s safe to take phen rx 377 mg along with 100mg of traZODone? Thanks

  15. Is it ok to take adipex with rexulti

    • Hi Rebecca,
      If this combination has been prescribed by a doctor then this is fine. If two different doctors are prescribing you these two medications then you should make sure that they are both fully aware of the other medication(s) you’re taking.
      Sally, phentermine.com

  16. Has anyone been prescribed phentermine and Saxenda together? I went to a weight clinic yesterday and have a prescription for both, but I am nervous about the combination.

    • How has this combination worked for you? What dosage of both are you taking??

  17. Can I take phen pro with my Lexapro? I also take 200mg of Lamictal at bedtime.

    • Hi Jessica,
      You should never combine phentermine with any prescription medication unless it has been specifically authorized by a doctor, so you should consult your prescribing doctor about taking these together, especially as Phen Pro already contains a low dosage of anti-depressant.
      Sally, phentermine.com

  18. I’m so confused now that I read this article. I just read on another site to NOT combine antidepressants and phentermine because it can be fatal and/or even put you on a coma. My PCP did not want to prescribe me phentermine and that’s why I had to go to a weight loss doctor to get them. I asked my PCP to wean me off Effexor so I can start taking phentermine. I took phentermine for 3 months and lost 30 lbs, no strict diet or exercise but now depression symptoms came back. I want to know if I can be on both.

    • Hi Veronica,
      Firstly, Phen Pro is phentermine with a very small amount of anti-depressant taken at the same time, so it’s different to taking the two drugs as they were individually intended – usually people who take Phen Pro do not have depression, it’s just a way that doctors have found that has shown improved weight loss results for a selection of patients. Secondly, it is possible for some people to take anti depressants and phentermine, but not everyone. Your PCP has your best interests at heart and is more familiar with your medical history than other doctors, so perhaps it would not necessarily be suitable for you for some reason.
      Sally, phentermine.com

    • How were you weaned off Effexor? I’ve tried once at a slow pace once and it was not good. I would love to get off of it. I was just prescribed phentermine and I’m on effecorporate and wellbutrin.

  19. Can you answer Jessica’s question from October 13th? I’m curious as well.

    • Hi Kellie,
      We haven’t spoken to anyone prescribed this combination so we’re not able to answer Jessica’s question. We were hoping that another reader would be able to offer their experience of taking Saxenda and phentermine together. Sorry we couldn’t be of more help but it doesn’t seem to be a very common combination so it’s hard to find information on it.
      Sally, phentermine.com

  20. Has anyone taken paxil with any of these diet pills?

  21. Can anyone tell me if taking Phentermine and Saxenda together is safe?

  22. Hi Roshanda- I was prescribe Saxenda and Phentermine together. I am on day one and feel okay. No appetite whatsoever. The nurse at the Dr’s office told me that patients has had good results on the combination of both. I will keep you posted.

  23. I started phen and prozac, lost only 6lbs. 2nd month only 2 lbs. So my Dr switched it up now I’m on phen and metFormin. I’m not having much success. He told me to play with it as directions to take these. I would love a little bit more instruction on how to take these to lose more weight. I’m only 20lbs from my ultimate goal weight. Could u please help me. Any ideas welcome. He is pretty willing to switch it up with me also. Thanks so much

    • Hi Misty,
      We don’t have much information about taking phentermine alongside Metformin, so if any of our readers can share anything then that would be great. Alternatively, you could try posting this message on our forum to see if anyone on there has experience of taking these two together.
      Sally, phentermine.com

  24. Taking Phentermine and Saxenda. Went from 226 to 210 in 3 weeks. Ran out of sample, given another sample of Saxenda while awaiting approval. Started back on 1.8 after being out 4 days. Having nausea, vomiting, unable to eat bad foods (food aversion). Today,only took phentermine. May try a lower dose of Saxenda tomorrow.

  25. I have been taking Citalopram for about three months now at 40mg a day, my Dr just prescribed my Adipex-P today at 37mg a day. Is it safe to take both of these medicatins together

    • Hello Sarah,

      Thank you for reaching out. We can’t offer you medical advice, you should ask your doctor about it as soon as you can. You are welcome to join our Facebook support group and connect with other phentermine users, today! https://www.facebook.com/groups/1069871763087734/

      Best regards

      Rebeca, Phentermine.com

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